minor changes

app.py

@@ -81,7 +81,15 @@ def swap_video(src_img, src_idx, video, dst_idx, progress=gr.Progress(track_tqdm
     for idx, frame_path in enumerate(frame_paths):
         out_path = os.path.join(swapped_dir, f"swapped_{idx:05d}.jpg")
         try:
-            swapped = swapper.swap_faces(src_path, int(src_idx), frame_path, int(dst_idx))
+            try:
+                swapped = swapper.swap_faces(src_path, int(src_idx), frame_path, int(dst_idx))
+            except ValueError as ve:
+                if int(dst_idx) != 1 and "Target image contains" in str(ve):
+                    # Fallback to dst_idx=1 if requested index not found in this frame
+                    swapped = swapper.swap_faces(src_path, int(src_idx), frame_path, 1)
+                    log += f"Frame {idx}: dst_idx {dst_idx} not found, used 1 instead.\n"
+                else:
+                    raise ve
             cv2.imwrite(out_path, swapped)
             log += f"Swapped frame {idx} and saved to {out_path}\n"
         except Exception as e: